Abstract:

In order to provide reference basis for developing effective investigation methods and prevention measures to be used on Valsa canker of fragrant pear tree, the author analyzed the damage and spatial distribution characteristics of Valsa canker on fragrant pear tree body in Korla and Aqsu, Xinjiang. The results showed that disease incidence was nearly 100% and also the occurrence degree of this disease was related closely with the management level of pear orchards. Disease incidence of Valsa canker on the trunk of pear was lowest, only 1.02%. The variance analysis in the number of scar and deadwood indicated that there were extremely significant differences among different wheel branches (the first, second, third branches), no differences among different direction (east, west, south, north). For the main branches and lateral branches, the number of scar had extremely significant differences, the number of deadwood showed no difference. The number of scar on both sides of twigs (the shaded and exposed side) had extremely significant differences. This disease occured mainly on the first wheel branches of peer. With increasing in the number of wheel branches, the number of scar and deadwood was significantly reduced. The occurrence degree of Valsa canker had no differences in different direction. The main harmful parts concentrated on main branches and lateral branches, especially the main branches. This disease occurred on the shaded side more serious than the exposed side of twigs.